Uses and Side Effects of Metamizole

Unlike other non-opioid analgesic drugs that act on the synthesis of prostacyclin, metamizole doesn't produce bad gastrointestinal effects. Today we'll tell you all about the popular Novalgin.
Uses and Side Effects of Metamizole
María Vijande

Reviewed and approved by the pharmacist María Vijande.

Written by María Vijande

Last update: 27 May, 2022

Metamizole is a drug that, in addition to being a potent anti-inflammatory, has other pharmacological actions as well. This is because it belongs to the family of pyrazolones which, in turn, are a group of drugs within NSAIDs or non-steroidal anti-inflammatory drugs. We’ll be looking at the uses and side effects of metamizole in this article.

Metamizole is an excellent treatment for pain and fever. So, companies market it in two different forms: sodium metamizole and magnesium metamizole.

Generally, people abuses this drug considerably. Being a fairly potent drug, it’s mainly recommended for patients with colics and in pain of oncological and internal origins. Also, to reduce post-surgical pain and lower the kind of fever that cannot be brought down by other medications.

Labs synthesized it in the year 1920. But it wasn’t until 1922 when they first introduced into the market under the “Novalgin” and “Dipyrone” brands, among others.

Today, labs sell metamizole under numerous trademarks worldwide and also under its generic names.

Fever overview

A woman looking at a thermometer.

Fever is a temporary increase in body temperature. An illness usually triggers it. In reality, fever is a defense mechanism that allows us to know that something out of the ordinary is happening in our body.

The normal human temperature is 98.6ºF, but it can have up to 1ºF of variation in healthy individuals. American entities defined fever at the central temperature greater than or equal to 100.9°F. That is just above the upper limit of normal human temperature, regardless of the cause.

Pyrogen induced fever occurs through several mechanisms. The interaction of external pyrogens, such as microorganisms. Or endogenous ones, such as interleukins IL. Also, the tumor necrosis factor TNF-alpha, together with a hypothalamus structure called organum vasculum of the terminal lamina, leads to the formation of fever.

However, fever isn’t only brought about by an infection, there may also be other causes that trigger it, such as:

  • Fever associated with inflammation
  • Drug-induced fever
  • Fever after a brain injury
  • Endocrine fever

How does metamizole trigger its effect on the body?

As we know, metamizole acts on pain and fever. Thus, it owes its action to its capacity to reduce the synthesis of pro-inflammatory prostaglandins. This is achieved, in turn, by inhibiting the activity of prostaglandin synthetase, which is an enzyme that catalyzes, as the name suggests, the synthesis of new prostaglandins.

Prostaglandins are substances of a lipid nature that participate, among many other processes, in inflammatory responses, by stimulating the nerve terminals of pain, and in the production of fever.

However, metamizole, unlike other NSAID drugs, is also able to inhibit fever induced by lipopolysaccharides. In addition, apart from inhibiting the synthesis of prostaglandins, it’s a non-selective inhibitor of the enzyme cyclooxygenase and from this inhibition derives its analgesic action.

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Side effects of metamizole

An array of pills.

Although metamizole is a very safe medicine, some European countries don’t commercialize it due to its side effects. Unlike other non-opioid analgesic drugs that act on the synthesis of prostacyclin, metamizole doesn’t produce important gastrointestinal effects.

However, like most drugs, metamizole can also trigger other types of side effects people must take into account at the time of administration.

The adverse effect that most stands out in the use of this medicine, and which a person must monitor closely, is agranulocytosis. In addition, it can also trigger leukopenia and thrombocytopenia. All these symptoms are hypersensitivity reactions.

In addition, some of the following effects may also develop:

  • Lyell and Stevens-Johnson syndrome.
  • Asthmatic crisis
  • Critical drops in blood pressure, which depend on the dosage.


Metamizole is a drug widely used by the general population for the treatment of pain and fever. However, you shouldn’t abuse it, since, like any medicine on the market, it can trigger a series of adverse effects. In addition, you must consult with your local pharmacist or doctor about the use of metamizole before starting any treatment with it.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.